SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828480c7dfcb723dd22fbbc839c417587c70bac669d1eaa94d81d30c3a5215bf' 
  AND token = 'mgCJtvSS7tqJaYwuoeRMykqaqXBZUoUVhPe/mGi4RNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}